MANCHESTER - Even seasoned court officers admitted surprise when they glanced up Wednesday to see one of New Hampshire most famous jurists waiting his turn to pass through the security check point at Hillsborough County Superior Court.

Retired U.S. Supreme Court Justice David H. Souter's impromptu visit to the renovated Chestnut Street courthouse came 46 years to the day that his first case was heard there, clerks said.

"He said he hadn't been in here since it was the old courthouse. He wanted to see the new courthouse," court officer Roger Bouchard explained of the building that reopened in October, 2011, after major renovations.

The 73-year-old Weare native - known for his privacy and thoughtful judicial opinions - arrived alone dressed neatly in suit and tie.

"He said he had his first case here on April 10, 1967," court officer George Lucas recounted.

Souter retired from the Supreme Court in June, 2009. He now lives in Hopkinton and is a visiting judge at the First Circuit Court of Appeals in Boston.

Souter was an associate at the Concord law firm of Orr and Reno from 1966 to 1968, became assistant attorney general and, in 1976, was named attorney general. Two years later, he was appointed to the Superior Court and was a sitting judge at the Manchester courthouse. President George H.W. Bush tapped him for the Supreme Court in 1990.

A court officer escorted Souter through the building with its gleaming glass atrium facade and renovated courtrooms - a far cry from the old courthouse's dark, cramped corridors and offices.

Souter met briefly with the court's four sitting judges and toured the downstairs during his approximately 30-minute visit then, just as quietly, slipped out the back door.